DailyTech reported several days ago that SSD
manufacturers have
been having problems with Samsung's latest generation of 32nm
NAND flash. The new chips have slow write speeds, thus making
them unsuitable for use in SSDs since that is one of the major
advantages that the new drives have over conventional hard drives.

We have received a reply from Samsung confirming the issue,
stating that "for quality SSDs, every NAND process geometry
upgrade requires a matching upgraded controller. Should
(Samsung's) 30nm-class NAND be used with a conventional controller of
insufficient quality, performance slowdowns are indeed
possible".

Flash memory stores information in arrays of
memory cells made from floating-gate transistors. As these
transistors scale to smaller process geometries, it becomes harder
for electrons to flow. This sometimes causes errors in writing to
memory cells which must be corrected through ECC (Error Correcting
Code). ECC is typically handled on the flash controller, which may be
overloaded by excessive write errors if it is not sufficiently
powerful enough. This is the most likely scenario for what is
happening.

Companies we spoke with confirmed similar
problems with 32nm flash from Toshiba that had been
overcome. Intel
is using 34nm flash from IMFT that was delayed from
mass production for six months, possibly due to a similar problem as
well.

Most of the SSD manufacturers we spoke with had paired
Samsung's flash with Indilinx's Barefoot flash controller. There are
several iterations of the Barefoot controller out there for different
SSDs, and no doubt Indilinx is working on the problem. However, it
might take a while, and sharp
price drops on SSDs are unlikely for several months.

Meanwhile, Samsung is currently in the process of completing a new
flash controller revision for their own line of SSDs, and have not
released any SSDs of their own using the new flash memory. Samsung
states: "We spend many months developing and then fine-tuning
the controller and firmware technology for our SSDs, working very
closely with most of the major PC OEMs".

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